The connexin family of proteins form hexameric complexes, called connexons, that facilitate movement of low molecular weight proteins between cells via gap junctions. Connexin proteins share a common topology of four transmembrane ?helical domains, two extracellular loops, a cytoplasmic loop and cytoplasmic N- and SLCtermini. Many of the key functional differences arise from specific amino acid substitutions in the most highly conserved domains; the transmembrane and extracellular regions. Connexin 31.9, also known as GJD3 (Gap junction delta-3 protein), is a 294 amino acid protein that interacts with ZO-1, a tight junction protein. Connexin 31.9 is expressed in heart, brain, kidney, spleen, lung, testis, colon and vascular smooth muscle cells. There are two isoforms of connexin 31.9 that are produced as a result of alternative splicing events.
Function:
One gap junction consists of a cluster of closely packed pairs of transmembrane channels, the connexons, through which materials of low MW diffuse from one cell to a neighboring cell.
Subunit:
A connexon is composed of a hexamer of connexins (By similarity). Interacts with TJP1.
Subcellular Location:
Cell membrane. Cell junction; gap junction.
Tissue Specificity:
Expressed in vascular smooth muscle cells. Found in heart, colon, and artery (at protein level). Found in cerebral cortex, heart, liver, lung, kidney, spleen and testis.
Similarity:
Belongs to the connexin family. Delta-type subfamily.
SWISS:
Q8N144
Gene ID:
125111
Database links:
Entrez Gene: 125111 Human
Omim: 607425 Human
SwissProt: Q8N144 Human
Unigene: 444663 Human
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